HELP Generics are important to Java because they enable the creation of code tha
ID: 3808895 • Letter: H
Question
HELP
Generics are important to Java because they enable the creation of code that is
a: Type-safe , b:Reusable, C: Reliable, D:all the above.
Can a primitive type be used as a type argument?
Yes, if the argument has more than one parameter
b.Yes, only primitive type can be used as a type argument
c. No, type argument must be object types
Show how to declare a class called FlightSched that takes two generic parameters.
a.class FlightSched<>{T, V},
class FlightSched(V, T) {
c.class FlightSched<generic, Integers> {
d.class FlightSched<T, V> {
Can the wildcard argument be bounded?
a.Yes, a wild card must have a lower bound only
b.Yes, a wild card must have an upper bound only
c.No, a wild card argument cannot be bounded.
d.Yes, a wild card can have either an upper or lower bound
.Do type parameters exist at run time?
a.No, some type parameters are erased during runtime
b.No, all type parameters are erased during compliation, and appropriate casts are substituted
c.Yes, all type parameters exist at run time
interface,
polymorphism
inheritance
none of the above ?
a.
Yes, if the argument has more than one parameter
Explanation / Answer
1. Generics are important to Java because they enable the creation of code that is
A. Type-safe
B. Reusable
C. Reliable
D. All of the above
Answer: D. All of the above
Can a primitive type be used as a type argument?
Yes, if the argument has more than one parameter
b.Yes, only primitive type can be used as a type argument
c. No, type argument must be object types
d.Yes, type argument does not have to be object types
Answer : c. No, type argument must be object types
Show how to declare a class called FlightSched that takes two generic parameters.
a.class FlightSched<>{T, V},
b.
class FlightSched(V, T) {
c.class FlightSched<generic, Integers> {
d.class FlightSched<T, V> {
Answer : d.class FlightSched<T, V> {
Can the wildcard argument be bounded?
a.Yes, a wild card must have a lower bound only
b.Yes, a wild card must have an upper bound only
c.No, a wild card argument cannot be bounded.
d.Yes, a wild card can have either an upper or lower bound
Answer : Yes, a wild card can have either an upper or lower bound
.Do type parameters exist at run time?
a.No, some type parameters are erased during runtime
b.No, all type parameters are erased during compliation, and appropriate casts are substituted
c.Yes, all type parameters exist at run time
d.No, all type parameters are erased during runtime, and appropriate casts are substituted
Answer : b.No, all type parameters are erased during compliation, and appropriate casts are substituted
All methods in an abstract class must be decalred as abstract methods
true/false ? False - An abstract class is a class that is declared abstract —it may or may not include abstract methods.
Invoking a subclass-only method through a subclass variable is not allowed
true/false ? false
If a superclass declares an abstract method, a subclass must implement that method.
true/false? true
An object of a class that implements an interface may be thought of as an object of that interface type
true/false? true
An annotation is syntactically based on a/an: Interface
a.Yes, if the argument has more than one parameter
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